Not content with delivering people to their destination, Uber is now delivering packages as well.

The company rolled out a new service on Monday called Rush, which lets people order pickup and delivery of packages using the Uber app. It's initially available only south of 110th Street in Manhattan, but Uber says it will expand that coverage quickly. If the service is successful, presumably it will bring it to other cities as well.

Packages are delivered by bike messenger or by foot, and users can select a pickup location in the app in much the same way they order a car today. Uber says a messenger will arrive within minutes. The user can then track the location of the package and share that location with the recipient.

It could be a smart move by Uber, whose car service is already popular among urban professionals -- the same type of people who use courier services today. And it piggybacks on the GPS in phones, allowing people to see how far their package has gotten.

Uber is just getting started with the service, and it notes that messenger availability will be limited to start. It also can't guarantee the accuracy of ETAs, and "tracking may pause if a messenger hops on the subway."

Still, it marks a new direction for Uber and is the latest example of an essentially offline service being turned into an on-demand mobile app. Uber and its rivals, including Lyft and Sidecar, have already turned the taxi business on its head.

Uber had apparently planned to announce the service Tuesday but news started to leak out early, partly because of Uber's not-so-subtle hints. "We're rolling out some big news on Tuesday," Uber said in a tweet Saturday posted to its New York City Twitter account, featuring a photo of a bicycle wheel.

It has also posted job ads on Craigslist to hire couriers. They'll be paid US$20-$30 per hour, the ad says, and be given an iPhone 4S so they can receive delivery orders.

There are already apps that help people get daily chores done, such as Postmates, WunWun and TaskRabbit. Uber notes that, unlike some of those apps, its couriers will not purchase items for delivery.